System and Method for Smoothing Power Reclamation of Blade Servers

ABSTRACT

A modular enclosure including first, second, third, and fourth servers, and a chassis management controller. The first, second, and third servers each have reclaimable power. The fourth server is configured to request a specific amount of power needed to complete a power-on request received at the fourth server. The chassis management controller is in communication with each of the first, second, third, and fourth servers. The chassis management controller is configured to reassign all the reclaimable power of the first server and to reassign a portion of the reclaimable power of the second and third servers to the fourth server.

FIELD OF THE INVENTION

This disclosure generally relates to information handling systems, andmore particularly relates to a system and method for smoothing powerreclamation of blade servers.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option is an information handling system. An information handlingsystem generally processes, compiles, stores, and/or communicatesinformation or data for business, personal, or other purposes. Becausetechnology and information handling needs and requirements may varybetween different applications, information handling systems may alsovary regarding what information is handled, how the information ishandled, how much information is processed, stored, or communicated, andhow quickly and efficiently the information may be processed, stored, orcommunicated. The variations in information handling systems allow forinformation handling systems to be general or configured for a specificuser or specific use such as financial transaction processing, airlinereservations, enterprise data storage, or global communications. Inaddition, information handling systems may include a variety of hardwareand software components that may be configured to process, store, andcommunicate information and may include one or more computer systems,data storage systems, and networking systems.

In a blade server rack, a priority rating may be assigned to each bladeserver. As blade servers are added to and/or removed from the rack, anamount of power provided to each blade server may change based on thepriority level of the blade server added to or removed from the serverrack. If a high priority blade server is added to the server rack, theamount of power provided to one or more lower priority blade servers maybe reduced so that the higher priority blade server receives the properamount of power. The lower priority blade servers have their powercorrespondingly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that for simplicity and clarity of illustration,elements illustrated in the Figures have not necessarily been drawn toscale. For example, the dimensions of some of the elements areexaggerated relative to other elements. Embodiments incorporatingteachings of the present disclosure are shown and described with respectto the drawings presented herein, in which:

FIG. 1 is a plan view of a front panel of a blade server rack;

FIG. 2 is a plan view of a back panel of the blade server rack;

FIG. 3 is a block diagram of a plurality of components within the bladeserver rack;

FIG. 4 is a graph of an amount of power provided to a plurality of bladeservers in the blade server rack; and

FIG. 5 is a flow diagram of a method for reclaiming power in the bladeserver rack to power on a high priority blade server.

The use of the same reference symbols in different drawings indicatessimilar or identical items.

DETAILED DESCRIPTION OF DRAWINGS

The following description in combination with the Figures is provided toassist in understanding the teachings disclosed herein. The followingdiscussion will focus on specific implementations and embodiments of theteachings. This focus is provided to assist in describing the teachingsand should not be interpreted as a limitation on the scope orapplicability of the teachings.

FIG. 1 shows a plan view of a front panel of a modular enclosure, suchas a blade server rack 100 of an information handling system. Forpurposes of this disclosure, an information handling system may includeany instrumentality or aggregate of instrumentalities operable tocompute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, or other purposes. For example, an informationhandling system may be a personal computer, a network storage device, orany other suitable device and may vary in size, shape, performance,functionality, and price. The information handling system may includerandom access memory (RAM), one or more processing resources such as acentral processing unit (CPU) or hardware or software control logic,ROM, and/or other types of nonvolatile memory. Additional components ofthe information handling system may include one or more disk drives, oneor more network ports for communicating with external devices as well asvarious input and output (I/O) devices, such as a keyboard, a mouse, anda video display. The information handling system may also include one ormore buses operable to transmit communications between the varioushardware components.

The blade server rack 100 includes a keyboard video monitor (KVM) port102, a power button 104, and a liquid crystal display (LCD) 106. Theblade server rack 100 is adapted to accept a plurality of servers, suchas blade servers 108. The blade server rack 100 may be installed in aserver chassis (not shown) such that the blade servers 108 can beconnected to each other and/or to other servers to form a network. TheKVM port 102 is configured to enable a user to connect a keyboard, adisplay monitor, or a mouse (not shown) to the blade server rack 100 andfurther configured to enable communication between the blade servers 108and the keyboard, the display monitor, and the mouse. The power button104 turns the power on and off to the entire blade server rack 100. TheLCD 106 can allow the user to check the status of the blade servers 108.The blade servers 108 can perform a variety of tasks, such as runningsoftware applications and storing and accessing data.

FIG. 2 shows a plan view of a rear panel of the blade server rack 100including a plurality of cooling fans 202, a plurality of power supplies204, chassis management controllers (CMCs) 206 and 208, a plurality ofinput output modules (IOMs) 210, and a local KVM 212. The cooling fans202 provide airflow over the different components of the blade serverrack 100. The power supplies 204 provide power to the differentcomponents of the blade server rack 100. The CMCs 206 and 208 cancontrol the power management in the blade server rack 100. The IOMs 210can enable the user to communicate with the blade servers 108 from aremote location. The local KVM 212 can allow the user to communicatewith the blade servers 108, to check the current status of the bladeservers, and the like from the keyboard, the display monitor, and themouse connected to the blade server rack 100.

FIG. 3 shows a block diagram of the blade server rack 100 includingblade servers 302 and 304, IOMs 306 and 308, and a chassis button module310 (including the power button 104). The blade server 302 includes aDell remote access controller (DRAC) 312, and the blade server 304includes a DRAC 314. The local KVM 212 includes an open source clusterapplication resource (OSCAR) module 316. The IOM 306 includes amanagement module 318, and the IOM 308 includes a management module 320.The CMC 206 includes a layer 2 switch 322, a CMC microprocessor unit(MPU) 324, and a chassis management module 326. The CMC 208 includes alayer 2 switch 328, a CMC MPU 330, and a chassis management module 332.

The blade server 302 is coupled to the blade server 304 and to the OSCARmodule 316. The DRAC 312 is connected to the DRAC 314, to the managementmodule 318, to the management module 320, and to the layer 2 switch 328.The blade server 304 is connected to the OSCAR module 316. The DRAC 314is connected to the management module 318, to the management module 320,and to the layer 2 switch 322.

The OSCAR module 316 is connected to the management module 318, to themanagement module 320, to the chassis management module 326, the chassismanagement module 330, and the power supplies 204. The management module318 is connected to the management module 320, to the layer 2 switch328, to the chassis management module 326, to the chassis managementmodule 330, and to the power supplies 204. The management module 320 isconnected to the chassis management module 326, to the layer 2 switch328, to the chassis management module 330, and to the power supplies204.

The layer 2 switch 322 is connected to the CMC MPU 324, to the layer 2switch 328, and to Intranet 334. The CMC MPU 324 is connected to thechassis management module 326. The chassis management module 326 isconnected to the power supplies 204, to the LCD panel 106, to thechassis button module 310, and to the fans 202. The layer 2 switch 328is connected to the CMC MPU 332, and to the Intranet 336. The CMC MPU332 is connected to the chassis management module 326. The chassismanagement module 330 is connected to the power supplies 204, to the LCDpanel 106, to the chassis button module 310, and to the fans 202.

The DRAC 312 can determine a maximum power requirement and a minimumpower requirement for the blade server 302. The maximum powerrequirement is the total amount of power needed when all of thecomponents within the blade server 302 are operating at a full load. Theminimum power requirement is the amount of power needed to power on theblade server 302 with only a few of the components operating. Upon theDRAC 312 receiving a power on request, the DRAC can request to receivethe maximum power requirement for the blade server 302.

The DRAC 314 can determine a maximum power requirement and a minimumpower requirement for the blade server 304. The maximum powerrequirement is the total amount of power needed when all of thecomponents within the blade server 304 are operating at a full load. Theminimum power requirement is the amount of power needed to power on theblade server 304 with only a few of the components operating. Upon theDRAC 314 receiving a power on request, the DRAC can request to receivethe maximum power requirement for the blade server 304.

During operation, a new blade server can be added to the blade serverrack 100 or a blade server already plugged into the blade server rack,such as blade server 302, can receive a power on request from the localKVM 212, from the CMC 206, from a remote user through the IOMs 306,through the layer 2 switch 322 from the user accessing a remote DRACwebsite. In either situation, the DRAC module 312 can send a powerrequest to chassis management module 326. The CMC MPUs 324 can performof set of instructions stored in a memory (not shown) of the CMC 206 tocarry out a power reallocation process when a new blade server is addedto the blade server rack 100. Even though the reallocation process isonly described with reference to CMC 206, it should be understood thatthe process could be performed by either the CMC 206 or 208, or by bothof the CMCs.

Upon receiving the power request, the CMC 206 can determine whetherthere is enough unused power available from the power supplies 204 tofulfill the power request from the blade server 302. If there is notenough unused power, then chassis management module 326 can throttle theblade servers down to the minimum power requirement. The chassismanagement module 326 also can request to receive a priority level ofeach of the blade servers 108 and an average amount of power used byeach of the blade servers from the DRACs. The priority level can differfor each blade server 108 in the blade server rack 100, and multipleblade servers can have the same priority level. For example, if thereare sixteen blade servers in the blade server rack 100, then three ofthe blade servers can have a lowest priority level, twelve of the bladeservers can have a middle priority level, and one can have a highestpriority level. The priority levels can be numbered such that a levelone priority represents the highest priority level, a level two priorityrepresents the middle priority level, and a level three priorityrepresents the lowest priority level.

To provide the blade server 302 with an amount of power equal to thepower request, the CMC 206 can reassign a portion of reclaimable powerin the blade servers 108, such as the blade server 304, to the bladeserver 302. Reclaimable power can be the difference between the maximumamount of power required by each of the blade servers 108 and theminimum amount of power required by the blade servers. The CMC 206 candetermine whether there is enough reclaimable power in the lowestpriority blade servers to fulfill the power request from the bladeserver 302. If there is enough reclaimable power, then the CMC 206 canreset a throttle current sensor (not shown) in the lowest priority bladeservers so that these blade servers only operate at the minimum powerrequirement. The chassis management module 326 can inform the DRAC 312that the blade server 302 can use the amount of power equal to the powerrequest.

If there is not enough power to fulfill the power request, then the CMC206 can determine an additional amount of power needed to fulfill thepower request. The CMC 206 also can determine a percentage of powerneeded to be taken from the blade servers having an equal prioritylevel, such as level two priority, to fulfill the power request. The CMC206 can reset the throttle current sensor on the blade servers havingthe level two priority such that these blade servers can only draw alower amount of power than the maximum amount allocated by the CMCs.Thus, the CMC 206 reduces the maximum amount of power level in all ofthe blades having the same priority level instead of reclaiming all ofthe power from a few blade servers of the plurality of blade servershaving equal priority. The chassis management module 326 can assign thereclaimed power to the blade server 302 having the highest priority.

FIG. 4 shows a plurality of bars 402-430 representing an amount of powerallocated to the blade servers 108. Bars 402-410, 414-420, and 424-430represent the allocated power to the blade servers having a level twopriority. Bars 412 and 422 represent the blade servers having a levelthree priority. The bars 402-430 also show the maximum power requirement432 and the minimum power requirement 434 for each of the blade servers108 in the blade server rack 100. Additionally, the bars 402-430 showthe amount of power reclaimed 436 from each of the blade servers 108when a new blade server having a level one priority is added to theblade server rack 100. In a particular embodiment, the reclaimed power436 for the blade servers having the level three priority is equal toall of the reclaimable power for the blade servers as shown by bars 414and 422. The reclaimable power is the difference between the maximumpower requirement 432 and the minimum power requirement 434. The powerreclaimed 436 in the blade servers having the level two priority is onlya percentage of the reclaimable power as shown by the bars 402-410,414-420, and 424-430.

The CMCs 206 and 208 can control the power allocation to the differentblade servers 108 within the blade server rack 100 so that enough poweris reclaimed to provide a high priority blade server with an amount ofpower requested for power on. FIG. 5 shows a flow diagram of a method500 for reclaiming power in a blade server rack to power on a highpriority blade server. At block 502, a power request is received from ablade server. A determination is made whether there is enough unusedpower in the server rack to provide the blade server with the full powerrequest at block 504. If there is enough unused power, then therequested amount of power is assigned to the blade server at block 506.At block 508, if there is not enough unused power, then the other bladeservers in the server rack are throttled back to a minimum working powervalue. The minimum working power value for a blade server is thesmallest amount of power needed for the blade server to be able tooperate.

At block 510, the amount of power needed for the power request isattempted to be reclaimed from the lowest priority blade servers. Adetermination is made whether enough power is now available for thepower request at block 512. If enough power is now available for thepower request, then the requested amount of power is assigned to theblade server at block 506. If enough power is not available for thepower request, then a minimum percentage of power reduction of equalpriority blade servers needed to fulfill the power request is determinedat block 514. At block 516, a determination is made whether the minimumpercentage is found. If the minimum percentage is not found, then adetermination is made whether a partial completion of the power requestcan be achieved at block 518. If a partial completion of the powerrequest can be achieved, then the flow diagram continues as stated aboveat block 514. If a partial completion of the power request cannot beachieved, then the power request from the blade server is denied atblock 520. If the minimum percentage is found, then a new power limit isassigned to the equal priority blade servers at block 522. The requestedamount of power is assigned to the blade server at block 506.

Although only a few exemplary embodiments have been described in detailabove, those skilled in the art will readily appreciate that manymodifications are possible in the exemplary embodiments withoutmaterially departing from the novel teachings and advantages of theembodiments of the present disclosure. Accordingly, all suchmodifications are intended to be included within the scope of theembodiments of the present disclosure as defined in the followingclaims. In the claims, means-plus-function clauses are intended to coverthe structures described herein as performing the recited function andnot only structural equivalents, but also equivalent structures.

1. A modular enclosure comprising: first, second, and third servers eachhaving reclaimable power; a fourth server configured to request aspecific amount of power needed to complete a power-on request receivedat the fourth server; and a chassis management controller incommunication with each of the first, second, third, and fourth servers,the chassis management controller configured to reassign all thereclaimable power of the first server and to reassign a portion of thereclaimable power of the second and third servers to the fourth server.2. The modular enclosure of claim 1 wherein the reclaimable power isreassigned to the fourth server from the first, second, and thirdservers based on priority levels of the first, second, third, and fourthservers.
 3. The modular enclosure of claim 2 wherein the priority levelof the first server is below the priority level of each of the secondand third servers, and the priority level each of the second and thirdservers is below the priority level fourth server.
 4. The modularenclosure of claim 1 wherein the chassis management controller isfurther configured to receive a priority level and an average powerconsumption for each of the first, second, and third servers.
 5. Themodular enclosure of claim 1 further comprising: an input output modulecoupled to each of the first, second, third, and fourth servers, theinput output module configured to provide a communication between aremote user and each of the first, second, third, and fourth servers,and further configure to provide the power-on request to the fourthserver from a remote user.
 6. The modular enclosure of claim 1 whereinthe first, second, third, and fourth servers are blade servers.
 7. Themodular enclosure of claim 1 further comprising: a keyboard video mousemodule coupled to each of the first, second, third, and fourth servers,the keyboard video mouse module configured to provide the power-onrequest to the fourth server.
 8. The modular enclosure of claim 1wherein the power-on request is received at the fourth server from thechassis management controller.
 9. The modular enclosure of claim 1wherein the power-on request is received at the fourth server from aremote website for controlling a module of the fourth server.
 10. Amethod of reassigning power in a system, the method comprising:receiving a power request from a first server; determining that there isnot enough unused power in the system to fulfill the power request;attempting to reclaim an amount of power needed for the power requestfrom reclaimable power of a second server; determining that thereclaimable power of the second server does not fulfill the powerrequest; determining a minimum percentage of power reduction of each ofthird and fourth servers that fulfills a remainder of the power request;and assigning the amount of power associated with the power request tothe first server.
 11. The method of claim 10 further comprising:throttling each of the second, third, and fourth servers to a minimumworking power value prior to attempting to reclaim the amount of powerneeded for the power request.
 12. The method of claim 10 furthercomprising: assigning a power limit to each of the second, third, andfourth servers.
 13. The method of claim 10 wherein the reclaimable poweris a difference between a maximum power requirement and a minimum powerrequirement for each of the second, third, and fourth servers.
 14. Themethod of claim 10 wherein a priority level of the first server ishigher than the priority levels of each of the third and fourth servers.15. The method of claim 14 wherein the priority levels of each of thethird and fourth servers is higher than the priority level of the secondserver.
 16. A method comprising: receiving a power request from a firstserver; determining a priority level of the first server; determiningthe priority levels of each of second and third servers; determiningthat the priority level of each of the second and third servers is lowerthan the priority level of the first server; determining a minimumpercentage of power reduction for each of the second and third serversbased on an amount of power to fulfill the power request; setting athrottle current sensor limit for each of the second and third serversbased on the minimum percentage of power reduction; and assigning theamount of power to fulfill the power request to the first server. 17.The method of claim 16 further comprising: determining reclaimable poweramount for a fourth server; and assigning the reclaimable power amountto the first server prior to determining the minimum percentage of powerreduction for each of the second and third servers.
 18. The method ofclaim 17 further comprising: determining the priority level for thefourth server; and determining that the priority level of the fourthserver is below the priority levels of each of the second and thirdprior to determining the reclaimable power amount for the fourth server.19. The method of claim 17 wherein the reclaimable power amount is adifference between a maximum power requirement allocated and a minimumpower requirement for the fourth server.
 20. The method of claim 16further comprising: preventing each of the second and third servers fromdrawing more power than allocated based on the throttle current sensorlimit.